In general, wild birds having coexisted with human beings for a long time have gone through the highly changed habitats by urbanization and industrialization followed by the development of civilization. Thus, specific birds are gradually decreased to become rare birds, species to be protected, but other birds are gradually increased as they are adapted to a change of environment.
Damages caused by birds, which were slight or seldom problematic in the past, have become more severe and even extended to a social problem. For example, damages to electric poles, airports, fish farms, bee farms, residential districts and other buildings as well as agricultural products are increasing step by step.
There are bird aversion methods used in protecting crops and facilities from harmful birds. These bird aversion methods employ: visual threatening products using a natural enemy model, a reflex mirror, a glittering tape, or the like; auditory aversion products using alarm sound, noise of radio or ultrasonic waves; contact products such as a protection net, a protection bag, a protection cap and the like; and products such as pasture liquid, naphthalene, methyl anthranilate, anthraquinone, and the like, which are mainly used in fruit farms.
While theses methods are used for exterminating birds giving harm to fruits, trees and facilities, they have lots of disadvantages such as a short-term effect and high cost and the like.
Bird aversion agents used for protecting crops and facilities from harmful birds are classified into primary and secondary bird aversion agents. The primary bird aversion agent is a formulation that is immediately able to prevent approaching of the birds by means of sight, taste, smell, stimulation and the like, and it does not need any learning effect.
The secondary bird aversion agent is also a formulation that causes pain by taking in foods and prevents ingestion of crops using a learning effect. Therefore, the secondary bird aversion agent is a material that leads to abnormal physiological and metabolic reaction when it is taken in, and exerts a unique effect only on harmful birds.
However, most of secondary bird aversion agents are agricultural chemicals or other chemicals, which have a latent problem causing environmental pollution and phosphorous-accumulated toxicity and the like due to their residuals. Further, the primary bird aversion agent has a disadvantage in that it usually has a slower durability effect than secondary bird aversion agent.
Recently, two types of bird aversion agents have been jointly used. Moason, et al. (1983) reported that effective bird aversion effects could be obtained when several chemicals or visual bird aversion compositions are added to methiocarb as secondary bird aversion agent. In addition, the combination of such primary bird aversion agent allows the effective concentration of secondary bird aversion agent to be remarkably reduced.
Therefore, there is an increasing need for development of an effective, eco-friendly bird aversion agent that can complement disadvantages of the conventional bird aversion agent.